Field of the Invention
The present invention relates to a coil component and a circuit board having the same and, more particularly, to a coil component using a drum-shaped core and a circuit board having the same.
Description of Related Art
In recent years, electronic components used for an information terminal such as a smartphone are strongly required to reduce the size and particularly height thereof. Thus, a large number of surface-mount type coil components not using a toroidal-shaped core but using a drum-shaped core exist as a coil component such as a pulse transformer. For example, Japanese Patent Application Laid-Open No. 2014-199906 discloses a surface-mount type pulse transformer using a drum-shaped core.
The drum-shaped core of the pulse transformer descried in Japanese Patent Application Laid-Open No. 2014-199906 has a configuration in which the mounting surface at the flange thereof has a concave-convex shape and the end portion of a wire is connected onto the convex part, as illustrated in FIG. 2 of Japanese Patent Application Laid-Open No. 2014-199906. On the other hand, a terminal electrode is not formed on the outer surface of the flange. With such a configuration, when the pulse transformer described in Japanese Patent Application Laid-Open No. 2014-199906 is mounted on a printed circuit board, a solder is formed between a land pattern on the printed circuit board and the convex part of the flange. Since the terminal electrode is not formed on the outer surface of the flange, a solder fillet is not formed on the outer surface.
In recent years, particularly, an on-vehicle coil component is required to have higher reliability than ever before. To meet this requirement, it is important to form a solder fillet when the coil component is mounted. It is necessary to form a terminal electrode on the outer surface of a flange in order to form a solder fillet; however, eddy current loss increase when a terminal electrode is formed on the outer surface of a flange.